Search

Adoptive cell therapies involving cell manipulation to achieve tolerance are increasingly being studied in animal models and in human trials. We have demonstrated that the specific removal of allo-stimulated dividing cells (or "pruning") promotes long-term allograft survival across a major MHC mismatch in transplant models including skin, heart and isiet transplants. In this study, we examine the role of transforming growth factor beta (TGFβ), an important regulatory cytokine, on allograft survival in our allodepletion or "pruning" skin transplant model. Increased proliferation of CD4+ T cells was observed following allo-stimulation of BALB/c spleen cells (labeled with CFSE) in the presence of the regulatory cytokines TGFβ and (interleukin-2) IL-2 in a mixed lymphocyte culture (MLC). Expression of the regulatory gene forkhead box-3 (FoxP3) was increased in both the allo-stimulated non-dividing (ND) (CFSEhigh) and dividing (D) (CFSElow) CD4+ T cell populations, with the highest expression found in tbe D CD4+ T cell population. Mice reconstituted with allo-stimulated ND CD4+ T cells following TGFβ/IL-2 stimulation sbowed prolonged allograft survival, similar to previous data. Significantly, TGFβ/lL-2 stimulation prevented acute rejection of allografts across a major MHC mismatch in the presence of highly activated allo-stimulated D CD4+ T cells. Blockade of TGFβ promoted rejection of allografts even following depletion of allo-stimulated D CD4+ T cells. Tbese studies support a crucial role for TGFβ in tbe survival of allografts and sbows tbat regulatory cytokines TGFβ/IL2 can delay tbe rejection of allografts, even in tbe presence of bighly activated alloreactive T cells. [ABSTRACT FROM AUTHOR]